2-(3,7-dimethylocta-2,6-dienyl)cyclopentan-1-one

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 28, 2019-

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-(3,7-dimethylocta-2,6-dienyl)cyclopentan-1-one

EC Number:

268-706-3

EC Name:

2-(3,7-dimethylocta-2,6-dienyl)cyclopentan-1-one

Cas Number:

68133-79-9

Molecular formula:

C15H24O

IUPAC Name:

2-(3,7-dimethylocta-2,6-dienyl)cyclopentan-1-one

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All concentrations at 0 and 72 hrs.
- Sample storage conditions before analysis: deep frozen

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock soltion was made by adding the appropriate amount of test substance to a volumetric flask. AAP-medium was then added to the mark. The solution was then ultrasonicated for 5 minutes, then stirred in the dark for 24 hrs. Undissolved test item was allowed to separate for 30 minutes. Volumes for the test solutions were then taken by Teflon tubling from the middle of the flask. Dilutions of the stock solution were then used to create the test solutions.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): Yes, surface film.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata (Korshikov) Hindák (Sphaeropleales: Selenastraceae)
- Source (laboratory, culture collection): MBM Sciencebridge GmbH
- Method of cultivation: Grown semi-continuously in sterile cultures. Algae are kept in an exponential growth state by periodically replacing the mineral solution.

ACCLIMATION
- Acclimation period: 3-4 days
- Culturing media and conditions (same as test or not): similar

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

22.4-23 degrees C

pH:

7.33-7.84

Nominal and measured concentrations:

Nominal: 0, 0.0800, 0.250, 0.750, 2.25, 6.75 mg/L

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: 50 mL
- Initial cells density: 0.5 x 10^4 cells/mL
- Control end cells density: 0.5 x 10^4 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Photoperiod: Continuously
- Light intensity and quality: 85.6 µEm-2s-1 (mean)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: fluorimeter
- Other: morphological appearance of cells

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 100, 10.0, 1.00, 0.100, 0.001 mg/L and control
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.85 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.94 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

biomass

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

biomass

Effect concentrations 4

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.75 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

biomass

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): No abnormalities were observed.
- Unusual cell shape: No
- Colour differences: No
- Other: No cells were observed at the 6.75 mg/L concentration.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 1.65 mg/L

Reported statistics and error estimates:

95% confidence limit for ErC50: 3.77-3.94 mg/L (nominal)

Any other information on results incl. tables

Concentration (mg/L)	Average Number Cells (10^4/mL)	Average Number Cells (10^4/mL)	% Inhibition in Growth Rate	Average Number Cells (10^4/mL)	% Inhibition in Growth Rate	Average Number Cells (10^4/mL)	% Inhibition in Growth Rate
	0 hrs	24 hrs	24 hrs	48 hrs	48 hrs	72 hrs	72 hrs
Control	0.6	1.97	0.0	10.38	0.0	54.76	0.0
0.0800	0.6	1.82	6.7	9.63	2.5	51.27	1.4
0.250	0.6	1.82	6.5	9.76	2.0	52.24	1.0
0.750	0.6	1.76	9.6	8.85	5.4	46.13	3.7
2.25	0.6	1.77	9.2	9.24	4.1	52.32	1.1
6.75	0.6	0.53	110.9	0.32	121.8	0.39	109.9

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72-hr EC50 based on growth rate was 3.85 mg/L (nominal). The 72-hr EC50 based on yield was 2.94 mg/L (nominal).

Executive summary:

The toxicity to algae of the test substance apritone was determined in an OECD guideline 201 study. Algae were exposed to nominal concentrations of 0, 0.0800, 0.250, 0.750, 2.25, and 6.75 mg/L for 72 hrs. No cells were seen at the 6.75 mg/L concentration. The 72-hr EC50 based on growth rate was 3.85 mg/L (nominal).  The 72-hr EC50 based on yield was 2.94 mg/L (nominal). The NOEC was 0.250 mg/L (nominal, based on yield), and the LOEC was 0.750 mg/L (nominal, based on yield).